15/04/2025
Will we, won't we? I suppose we will soon find out!
Heads up aurora chasers! Tomorrow, we could see aurora down to mid-latitudes including the U.S.-Canada border, central Europe, New Zealand, and Tasmania. G2/Kp 6 conditions are currently anticipated. Let's break down why this happening, and who will see aurora at what times!
What is going on? A big "sun sneeze" or CME was released from the Sun yesterday as a result of a plasma filament snapping away in the Sun's atmosphere. This released a big cloud of charged particles that are heading towards Earth. We know this because we saw the explosion come off the Sun, and it looked like it was heading right at us (fall halo signature). Scientists and modelers at the NOAA Space Weather Prediction Center determined this is heading at Earth and released models showing when it may hit us. A moderate geomagnetic storm watch has been issued for tomorrow, and we may see impact Tuesday midday leading to increased probabilities of geomagnetic storming through the night.
When is it happening? Nothing is guaranteed. The CME may not even hit us. Some models like the HUXt model (more info: https://go.theauroraguy.com/huxtmodel) are saying there is a 95% chance of impact, but that still leaves room for a miss. So far, I have looked at arrival time predictions from NASA, NOAA, and HUXt. All of them say we should expect the CME to arrive Tuesday midday (North America timezones). There is a ~7-hour uncertainty with these arrival times, so it could arrive earlier or later. CME effects typically last 12-24 hours, so the hope is that even if it hits during the day or morning for us here in North America, the CME will be strong enough to cause geomagnetic storming to persist until nightfall.
Who will see aurora? This depends on a LOT of factors. First, geomagnetic storms just cause the auroral ovals to expand a little bit to the equator. This may cause auroras to be seen throughout the night along the U.S.-Canada border without the influence of substorms. Substorms (more info: https://go.theauroraguy.com/substorm) are what really get the aurora juiced up and cause people to see it from further away. They're what cause the aurora to dance and get those intense red colors that can be seen from really low-latitude places like Texas, Arizona, or California (for example). You can track the substorm using the GOES magnetometers (tutorial: https://go.theauroraguy.com/goesmag) or we**ams (https://go.theauroraguy.com/we**ams ; if you see aurora and the we**am is near you, then go out!). You also need clear skies and having a darker sky (not as much light pollution) to the north is helpful, too. We can see strong substorms even if Kp is "low" (like 4 or 5), so do't use the Kp or Kp predictions to forecast the aurora or monitor it in real-time, it won't work!
How can you stay up-to-date? You can follow me or look for the arrival of the CME yourself in solar wind data. I have a tutorial on this on my blog (https://go.theauroraguy.com/auroraprediction) and in my free e-book (https://go.theauroraguy.com/ebook). My free e-book is a great resource to get some more context on space weather, aurora science and forecasting, and how to chase! It's free when you sign up for my e-mail list, and you will join over 27,000 other people who have already signed up! Follow the link here: https://go.theauroraguy.com/email.
Do's and Dont's for tomorrow?
Don't use the Kp index.
Don't use the OVATION model to forecast substorms (it's not a real picture of the aurora!).
DO check we**ams.
DO check Facebook groups, Aurorasaurus, and other social media to see where people are spotting the aurora.
DO check your skies with a camera/iPhone to see if the aurora is out but is too dim to see with your naked eyes.
DO stay safe if you go out by staying in cell range, driving on public, paved roads, packing snacks and water, wearing extra warm weather layers, and telling someone where you're going and when you will be back.
DO turn off your headlights if you are parked trying to see the aurora and use a red headlamp if you have one.
Finally, DO ask questions if you have any, and I'll try and respond as soon as I can.
Happy hunting, and remember, nothing is ever guaranteed in aurora chasing, but we lower expectations, we will always be pleasantly surprised :). Let's cross our fingers for a good CME impact, substorms, and clear skies tomorrow!
Discover the wonders of the night sky with Wales' premier astronomy adventures and educational services. Ever considered what's above your head?
